I’ve had an Apex 2016 in my 65g tank since Nov 17, and overall the experience has been good. I am planning a 2nd 140g tank and will definitely be buying a second unit for that. I run the 4 standard probes, an ATK with FMM, 2 DOS heads and an AFS I use occasionally. I control my return, wavemaker, skimmer and main heater. I power my chiller with programming for a ‘fail on’. I run a small UPS with a keep-alive Apex program for short outages.
I am also seriously considering setting up an auto-fill for my RODI and AWC setup, which would mean 2 more DOS, one more FMM, a PMUP, couple of solenoids and optical sensors. I don’t have experience with GHL so can’t comment on that.
I have had an issue with the FMM a few times where it stops turning the PMUP on and needs a power cycle to get it working again. It has only happened 4 times in the nearly 2 years however and the automation alerts me to the issue as soon as it happens.
I did need to recalibrate the salinity probe a second time and spend quite a bit of time fiddling with temperature compenstation before I felt it was reliable, but think this is good practice in any case. I suggest calibrating the Ph and Salinity probes when you first setup the Apex, and for the next few months fiddle with the temperature compensation until you feel it is stable. After 3 months or so re-calibrate both probes. I haven’t had to recalibrate since then myself and they are both fairly accurate. I only use them for trend analysis in any case, not absolute readings.
Regards and happy reefing.